EP0429996A2 - Verfahren zur Methylierung eines gehinderten Stickstoffatoms in einem inerten nichtwässerigen Lösungsmittel - Google Patents

Verfahren zur Methylierung eines gehinderten Stickstoffatoms in einem inerten nichtwässerigen Lösungsmittel Download PDF

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Publication number
EP0429996A2
EP0429996A2 EP90121992A EP90121992A EP0429996A2 EP 0429996 A2 EP0429996 A2 EP 0429996A2 EP 90121992 A EP90121992 A EP 90121992A EP 90121992 A EP90121992 A EP 90121992A EP 0429996 A2 EP0429996 A2 EP 0429996A2
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EP
European Patent Office
Prior art keywords
methylated
complex amine
psp
groups
water
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Application number
EP90121992A
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English (en)
French (fr)
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EP0429996A3 (en
Inventor
Pyong-Nae Son
Victor Lacson Ledesma
George Kletecka
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Goodrich Corp
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BF Goodrich Corp
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Publication of EP0429996A2 publication Critical patent/EP0429996A2/de
Publication of EP0429996A3 publication Critical patent/EP0429996A3/en
Withdrawn legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D403/00—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, not provided for by group C07D401/00
    • C07D403/02—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, not provided for by group C07D401/00 containing two hetero rings
    • C07D403/12—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, not provided for by group C07D401/00 containing two hetero rings linked by a chain containing hetero atoms as chain links
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D403/00—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, not provided for by group C07D401/00
    • C07D403/14—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, not provided for by group C07D401/00 containing three or more hetero rings

Definitions

  • This invention relates to a process for methylating a hindered nitrogen atom in the diazacycloalkane ring of a piperazine or piperazin-2-one which is substituted at both the 3- and 5- positions of the diaza ring.
  • Such compounds are referred to as polysubstituted piperazine or piperazinone ("PSP" for brevity) compounds.
  • PSP polysubstituted piperazine or piperazinone
  • the N 4 atom is hindered in all such PSPs. This N 4 atom is termed "the hindered N atom" because it is flanked by disubstituted 3-and 5-carbon atoms, either or both of which may have a spiro substituent.
  • PSP-substituted compounds Compounds containing one or more PSP substituents are referred to as "PSP-substituted" compounds.
  • An example of such compounds are triazine compounds having PSP substituents.
  • the process of this invention is specifically related to the methylation of PSP-substituted triazine compounds.
  • Methylated PSP-substituted triazine compounds are excellent stabilizers for polyoxymethylene resins, particularly polyacetals.
  • Hindered amines having a methylated hindered N atom are highly desirable stabilizers for synthetic resinous materials, and command a premium price in the marketplace, whether the amine is a piperidine, piperazine or a piperazin-2-one derivative.
  • Several methylated PSP stabilizers have been disclosed in Japanese patent application 63-86711 published April 18 1988. These stabilizers are said to improve the color of polyacetals though the PSPs are not connected to a triazine ring. There is no teaching of how such methylated compounds were prepared, but it is known that the high cost of producing the stabilizers confines their syntheses to the laboratory. Our process is directed to providing an economical solution to a difficult manufacturing problem.
  • the typical E-C reaction carried out with a primary or secondary amine, results in the methylated amine only when heated for several hours after the evolution of gas has ceased due to reaction with an excess of formaldehyde and an excess of formic acid in an aqueous medium.
  • the formic acid functions as both a co-reactant and a solvent.
  • the function of formic acid as a solvent is particularly important when the amine to be methylated is poorly soluble in water.
  • the amine to be methylated is N 1 ,N 2 ,N 3 ,N 4 --tetrakis-[2,4-bis[N-(2,2,6,6-tetramethyl-4-piperidyl)-n-butylamino]-1,3,5-triazin-6-yl]-4,7-diazadecane-1,10-diamine, and it has 8 tetramethyl-4-piperidyl substituents.
  • To a solution of 0.02 moles of this amine in 100 ml of water is added 0.4 moles of formic acid and 0.4 moles of a 40% aqueous formaldehyde solution (each a 2-fold molar excess with terminal -NH groups).
  • the solution is heated under reflux for 8 hr; after cooling to room temperature, an additional amount of 0.2 moles (stoichiometric) of 40% formaldehyde is added and the solution refluxed for an additional 5 hr.
  • essentially dry conditions we refer to a reaction mass which has less than 3% by weight (wt) water present after the reaction is complete and the reaction mass is essentially a single organic phase.
  • wet we refer to a reaction mass in which there is at least 3% by wt water, but no more than about 30% by wt water, so that both aqueous and organic liquid phases are visually discernible.
  • reaction when the reaction is carried out at above about 60°C C0 2 formed during the reaction is driven off.
  • a higher temperature shortens the time for the reaction, producing the methylated tertiary amine, substantially quantitatively, typically in less than 8 hr.
  • solvent phase we refer to the solution of organic material in the alkylbenzene solvent. This ability to wash out essentially all impurities from the solvent phase, including unreacted formaldehyde, formic acid and salt formed upon neutralization, enhances the efficiency of, and vastly simplifies the recovery procedure for the methylated product.
  • Our process relates specifically to a modification of the well-known E-C procedure, which modification makes it possible to prepare PSPs and PSP-substituted compounds containing a methylated hindered N atom, on a commercial scale, economically.
  • Our process is carried out in the presence of an inert organic liquid medium which is a solvent for the reactants and the desired methylated product, the solvent being chosen for its favorable partition coefficient for the methylated product in an aqueous system.
  • the solvent is preferably an aromatic liquid such as an alkyl benzene chosen from ethylbenzene, trimethylbenzene, xylene, and most preferably toluene.
  • the compound to be methylated is dispersed in the solvent and the reaction is carried out with a specified slight excess of paraformaldehyde and formic acid.
  • aqueous alkali is added only after the methylation reaction is complete, since the boost due to the reducing action of the alkali metal salt is not only unnecessary in our E-C reaction, it serves only to pre-neutralize formic acid.
  • inert we refer to a solvent which is unreactive with the compounds in the reaction mass under the conditions of the reaction.
  • the hindered N 4 atom of a polysubstituted piperazine or piperazine-2-one may be methylated using a modified Eschweiler-Clarke ("E-C") procedure which requires carrying out the reaction under either "wet” or “essentially dry” conditions, in less formic acid than will form a solution with the PSP, so as to produce the N 4- methylated product in an alkylbenzene solvent which can be washed with water to obtain the methylated product in an yield in excess of 90%.
  • E-C Eschweiler-Clarke
  • a complex amine including a triazine ring with at least one PSP substituent (referred to as a "PIP-T" for brevity) has a peculiarly attractive partition coefficient in a mixture of an alkylbenzene ("solvent phase"), and water (“aqueous phase)".
  • solvent phase an alkylbenzene
  • aqueous phase water
  • This coefficient allows the solvent phase to be washed with water to remove unreacted formaldehyde, formic acid and by-product impurities, yet transferring less than 1% by wt of the methylated PSP or PIP-T from the solvent phase to the aqueous phase. Therefore harvesting product from both phases is avoided.
  • m represents an integer in the range from 1 to 6, being the number of methylene groups some of which, (a) together with the carbons to which they are bound, may form a cyclopentyl, cyclohexyl or cycloheptyl endo ring, or (b) be substituted;
  • the best mode of our process relates to methylation of PIP-Ts such as those disclosed in U.S. Patent Nos. 4,480,092; 4,629,752; 4,639,479. At least the hindered N 4 atom of each NH group, and preferably every other terminal -NH group in each PSP-substituted compound is to be methylated.
  • PIP-Ts are typically prepared by substituting at least one, and most preferably, each of two or three chlorine (or other halogen) atoms on a di- or trihalo-s-triazine, specifically cyanuric chloride, with a PSP, so as to form a substituted triazine.
  • a di- or trihalo-s-triazine specifically cyanuric chloride
  • PSP cyanuric chloride
  • a particular PIP-T is formed by the reaction of cyanuric chloride with a particular PSP amine reactant, 1-[3-(cyclohexylamino)propyl]-3,3,5,5-tetramethylpiperazin-2-one, familiarly referred to as cyclohexyl- piperazinone, ("CHP" for brevity), represented by the structure:
  • PIP-T heterocylic amine which is to be methylated is represented as follows: wherein PSP represents the same structure written for the other substitutent.
  • the PIP-Ts are formed by reaction of cyanuric chloride with the following polysubstituted piperazin-2-ones:
  • PIP-Ts whether di- or tri-substituted, may be formed by reaction of cyanuric chloride with the following polysubstituted piperazines:
  • the reaction mass obtained is a colored oil which, when cooled to room temperature, is highly viscous.
  • To precipitate the methylated product from this oil it is heated to about 80°C and 1 liter of water added to obtain a slurry having a pH of about 3. When this slurry is neutralized with a large excess of 25% NaOH solution, a foamy solid is precipitated.
  • the neutralized solution is filtered.
  • the aqueous filtrate contains a substantial amount of VIII which does not precipitate.
  • the white filter cake (965 g) is washed with about 2 liter of demineralized (DM) water in a 5 liter flask, and filtered.
  • the paraformaldehyde HO(H 2 CO) n H used is 96% commercial grade which contains about 4% water; the formic acid used is 90% commercial grade; and the PIP-T having the structure VII is essentially pure and dry.
  • the preferred molar ratio of NH groups in the PIP-T : HCHO : HCOOH is in the range from about 1:1.02:1.02 to 1:1.1:1.2.
  • the percent excess (used in this run for methylating VII) over stoichiometric of paraformaldehyde is 10%, and of HCOOH is 20%.
  • the amount of toluene added is such that the weight ratio of toluene to methylated product (to be theoretically formed) is in the range from about 2 to about 4, depending upon the solubility of the product in toluene, and for methylated PIP-T'VIII is preferably in the range from about 2 to about 2.75.
  • Toluene is favored for methylating VII but another alkylbenzene may be chosen for another PIP-T, particularly one represented by structures Va or Vb.
  • the reaction mass is then cooled to 60°C, and enough aqueous 25% NaOH or NH4-0H is added to neutralize the excess formic acid. If alkali is added before the reaction is complete, the amount of formic acid in the reaction mass is depleted and serves to slow rather than accelerate the desired reaction.
  • the water phase is separated and discarded since its concentration of methylated PIP-T in the water phase is less than 1%, and more preferably less than 0.1% of theoretically produced product. Recovery of methylated product from the water phase is neither necessary nor economically justified.
  • the formaldehyde and sodium (or ammonium) formate are also present, but in too low an amount to be economically recoverable, yet low enough a concentration to be biodegradable.
  • the toluene phase is washed with hot DM water several times, mixing thoroughly for a period of 15 min each time at 50-60°C, before settling.
  • the washed toluene solution is stripped to concentrate it until less than half the toluene remains.
  • To this concentrated slush of the methylated PIP-T in toluene is added enough cool heptane to precipitate solid methylated product, forming a slurry.
  • the slurry is centrifuged, and washed with more heptane in the centrifuge, before the cake is removed and dried.
  • the filtrate from the centrifuge is recovered for reuse.
  • the essentially pure methylated PIP-T VIII recovered is found to be more than 95% by weight of theoretical, illustrating that use of toluene as a solvent permits obtaining more than 95% of theoretical product, economically, in a single harvest from the reaction mass.
  • the reaction may be carried out at substantially atmospheric pressure below reflux temperature but above about 60°C, but the lower temperature will prolong the time required to complete the reaction.
  • the reaction may be carried out under elevated pressure in the range from 2 to about 5 atm at the reflux temperature of the alkylbenzene solvent, or the azeotrope (the toluene-water azeotrope refluxes at about 84°C at substantially atmospheric pressure) to speed up the reaction.
  • water may be removed from the azeotrope and the toluene returned to the reactor.
  • the reaction may then be continued at the boiling point of the solvent (about 110°C for toluene).
  • the reaction may be carried out at as high a temperature as will produce a tolerable amount of byproducts. Higher temperatures, if desired, may be obtained with an appropriate choice of solvent. A temperature above 150°C will generally be too high to maximize the production of methylated product.
  • methylation of the PIP-T VII is carried out under "wet" process conditions using the same molar quantities of reactants, except that the PIP-T solids to be methylated are wet (containing from 30% to 60% water), and 37% form aldehyde and 90% formic acid are used so that the amount of water in the reaction mass is about 26% by weight (after the reaction is complete).
  • the amount of toluene added is enough to give a toluene:product ratio of about 2.3.
  • the reaction is carried out under total reflux, at the reflux temperature of the toluene-water azeotrope, the higher temperature being used to speed up the reaction. Progress of the reaction is monitored as before, and the reaction is complete in about 12 hr.
  • the reaction may be carried out under more dilute conditions, but serves no economic purpose since the presence of additional water and toluene serves to decrease the productivity (pounds product/unit volume of reactor) of the process.
  • reaction mass is cooled, neutralized and worked up as before. Less than 1% by weight of the methylated product is lost in the water, and the yield of recovered product is greater than 95%.
  • a reaction vessel 10 provides a reaction zone for obtaining essentially complete conversion of the PIP-T after the reactants are in solution in the solvent introduced.
  • the first step in which the PIP-T, paraformaldehyde, formic acid and toluene are charged, is identified by reference numeral 1 written in a circle to distinguish the symbol from numerals used to identify equipment.
  • the PIP-T may be charged as an essentially dry powder, or as a toluene-wet cake or slurry, or as a solution in toluene, or other alkylbenzene solvent used, since the PIP-T must be in solution when it is methylated.
  • the PIP-T may be charged as a water-wet cake, or a slurry in water, since a small amount of water, most preferably about 10% or less, does not prolong the time for methylation unacceptably.
  • step 2 neutralization of the contents of the reactor either with a solution of an alkali metal hydroxide or ammonium hydroxide (identified as step 2), results in an aqueous layer which is conveniently drained (step 3) from the reactor.
  • the solution of methylated PIP-T in alkylbenzene, specifically toluene, is washed with distilled water, several times if necessary, to remove formate and unreacted paraformaldehyde, and any water-soluble byproducts which may be formed.
  • the wash water is drained from the reactor in step 4.
  • Toluene is then stripped (step 5) from the washed toluene phase, until a super-saturated solution remains. Toluene is withdrawn from the reflux condenser 11 into a condensate receiver 12 for later reuse. A surge tank 13 is provided for safety reasons.
  • the methylated PIP-T is then precipitated from the super-saturated solution, for example by cooling the hot super-saturated solution.
  • This method is referred to as "direct precipitation”.
  • a precipitating agent is added, this method being referred to as “assisted precipitation”.
  • concentration of the solution of methylated PIP-T in toluene, precipitation of the methylated PIP-T, and washing out the unreacted formaldehyde, formic acid and impurities are done in the reactor to avoid transferring the contents of the reactor, after the reaction is completed, to another vessel(s) for "work-up” and recovery of the essentially pure methylated PIP-T.
  • methylated PIP-T may not always be a crystalline solid, though the compound VIII is.
  • the particular choice of precipitating agent depends upon how poor a solvent it is for a specific methylated PIP-T, providing of course the precipitating agent is miscible with the alkylbenzene. By “miscible” is meant that the precipitating agent and alkylbenzene form a single liquid phase.
  • methylated PIP-Ts represented by structures Va, Vb and Vc are essentially insoluble in acetone, methylethyl ketone, or another Ci-G2 2 alkyl ketone, one of which may provide a satisfactory precipitating agent.
  • step 6 addition of heptane to the super-saturated solution of VIII in toluene (step 6), precipitates VIII.
  • a large amount of heptane is used, this amount (by wt) being substantially greater than the weight of toluene, preferably 2 to 10 times more heptane than toluene, so as to form a slurry of solid VIII in a heptane rich mixture of heptane-toluene.
  • the slurry of VIII in the heptane-toluene mixture is flowed to a centrifuge 14, in which the centrifuged solids are washed with successive washes of heptane to free the cake from toluene.
  • the filtrate (or "centrate") from the centrifuge is recovered for reuse.
  • the cake from the centrifuge is then dried in a vacuum oven 15, but, because of the extreme solubility of VIII in toluene, typically still contains more than about 100 ppm but less than 1 % by wt of toluene. This dried product, essentially free of alkylbenzene solvent, is then transferred to suitable containers.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Plural Heterocyclic Compounds (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
EP19900121992 1989-11-21 1990-11-17 Process for methylating a hindered nitrogen atom in an inert non aqueous-solvent Withdrawn EP0429996A3 (en)

Applications Claiming Priority (2)

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US07/439,749 US5239071A (en) 1989-11-21 1989-11-21 Process for methylating a hindered nitrogen atom in an inert non-aqueous solvent
US439749 1995-05-12

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EP0429996A2 true EP0429996A2 (de) 1991-06-05
EP0429996A3 EP0429996A3 (en) 1992-01-22

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EP (1) EP0429996A3 (de)
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0447973A3 (en) * 1990-03-19 1992-03-25 The B.F. Goodrich Company Alkylated oxo-piperazinyl-triazine
EP1513845B2 (de) † 2002-06-20 2010-11-03 Adamed SP. Z O.O. Verfahren zur herstellung von olanzapin und ein zwischenprodukt dafür
CN106565007A (zh) * 2016-11-09 2017-04-19 烟台史密得机电设备制造有限公司 一种三元复合驱采出水的除油剂及其制备方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100414436B1 (ko) * 2001-06-14 2004-01-07 모두식 섬유방사의 오일 확산 방법

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4190571A (en) * 1977-09-21 1980-02-26 The B. F. Goodrich Company Substituted 2-keto-1,4-diazacycloalkanes and UV-light-stabilized compositions containing them
US4480092A (en) * 1982-02-19 1984-10-30 The B. F. Goodrich Company Alkylated polyalkylenepolyamines, substituted oxo-piperazinyl-triazines
US4639479A (en) * 1982-02-19 1987-01-27 The Bfgoodrich Company Polyalkylenepolyamine having pendant substituted oxo-piperazinyltriazines and UV light stabilized compositions
US4629752A (en) * 1985-07-22 1986-12-16 The B. F. Goodrich Company Substituted oxo-piperazinyl-triazines and UV light stabilized compositions
US4780495A (en) * 1986-07-21 1988-10-25 The B. F. Goodrich Company N-(substituted)-α-(3,5-dialkyl-4-hydroxyphenyl)-α,α-disubstituted acetamides, and composition stabilized therewith
IT1197466B (it) * 1986-08-25 1988-11-30 Ciba Geigy Spa Metodo per la stabilizzazione di polimeri oleofinici mediante composti triazinici
IT1217315B (it) * 1987-03-24 1990-03-22 Ciba Geigy Spa Composti triazinici derivati dalla 2,2,6,6-tetrametilpiperidina
IT1205023B (it) * 1987-05-22 1989-03-10 Ciba Geigy Spa Composti piperidin-triazinici utilizzabili come stabilizzanti di poliolefine
IT1223405B (it) * 1987-12-04 1990-09-19 Ciba Geigy Spa Procedimento per la metilazione di composti triazinici contenenti gruppi 2,2,6,6 tetrametilpiperidinici

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0447973A3 (en) * 1990-03-19 1992-03-25 The B.F. Goodrich Company Alkylated oxo-piperazinyl-triazine
EP1513845B2 (de) † 2002-06-20 2010-11-03 Adamed SP. Z O.O. Verfahren zur herstellung von olanzapin und ein zwischenprodukt dafür
CN106565007A (zh) * 2016-11-09 2017-04-19 烟台史密得机电设备制造有限公司 一种三元复合驱采出水的除油剂及其制备方法

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JPH03284677A (ja) 1991-12-16
KR910009694A (ko) 1991-06-28
EP0429996A3 (en) 1992-01-22
US5239071A (en) 1993-08-24

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